Characterization, quantification of free, esterified and bound phenolics in Kainth (Pyrus pashia Buch.-Ham. Ex D.Don) fruit pulp by UPLC-ESI-HRMS/MS and evaluation of their antioxidant activity

UPLC-ESI-HRMS/MS was used to identify the free, esterified and bound phenolic compounds in Kainth fruit extracts. In total, around 17, 15 and 18 free, esterified and bound phenolic compounds respectively were identified. Among these, Procyanidin B-2, Epicatechin, Phloridzin, Hesperetin, etc. are being reported for the first time. The total phenolic content of free, esterified and bound fractions were 178.33 +/- 6.90, 151.33 +/- 7.73 and 707.16 +/- 19.77 mg GAE/100 g of fruit. The major phenolic compounds quantified were chlorogenic acid (7.97 mg/100 g), arbutin (7.05 mg/100 g) and catechin (44.56 mg/100 g) in free, esterified and bound form respectively. Various antioxidant assays (DPPH, ABTS, TAC and FRAP) were performed for all the extracts. Among different extracts, the bound phenolics exhibited the highest antioxidant activity. Systematic identification and quantitative profiling of phenolics in Kainth fruit being presented for the first time would help in utilising this fruit for designing functional food formulations.